(Ch. 8 and 9)
Enzymes
Cellular Respiration
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| chemical factories | ||
| all of an organisms chemical reactions, highly organized | ||
| - downhill pathway, energy released, (ex. cellular respiration) | ||
| -uphill pathways, require input of energy, (ex. building a protein) | ||
| the capacity to cause change | ||
| based on position or place (on a ledge=high) | ||
| potential energy continued in molecules | ||
| relative motion, heat/thermal (by random movement) | ||
| 1: Energy can be transferred or transformed, but it cannot be created or destroyed 2: Every energy transfer or transformation increases the disorder of the universe | ||
| is a measure of a system's instability (or tendency to move to a more stable state) *deltaG= deltaH-TdeltaS | ||
| energy outward, spontaneous (bonds being broken and formed) | ||
| energy inward, absorbs free energy, not spontaneous | ||
| dead | ||
| use an exergonic process to drive an endergonic one (hydrolysis of ATP) | ||
| a chemical reagent that speeds up a reactions without being consumed by the reaction (lowers free energy of activation) | ||
| speed up metabolic reactions, lower the free energy of activation. | ||
| used by enzymes when a substrate binds to an active site and the enzyme squeezes around the substrate. | ||
| 1. Initial substrate concentrations (saturation) 2. Environmental conditions (temp, pH) 3. Cofactors (Coenzyme) 4. Enzyme inhibitors (Competitive,Noncompetitive) | ||
| 35-40 degrees Celsius | ||
| 2 (acidic) | ||
| 8 ( basic) | ||
| substrate binds to active site | ||
| a competitive inhibitor binds to active site *can prevent by adding a bunch of substrate | ||
| noncompetitive inhibitor binds the other binding site beside the active one. | ||
| Enzyme's function at one site is affected by the binding of regulatory molecules at another site (activators and inhibitors) p. 4 of lecture notes on enzymes | ||
| End product switches off the metabolic pathway | ||
| in specific locations within cells | ||
| -process by which cells harvest the chemical energy stored in organic molecules and use it to generate ATP - 3 key pathways: glycolysis, citric acid cycle, oxidative phosphorylation | ||
| Oxidation ( loses electron) Reduction (gains electron) | ||
| electron donor | ||
| electron receptor | ||
| exergonic | ||
| occurs without the input of energy | ||
| -glucose and other organic fuels are broken down in a series of steps, each one catalyzed by an enzyme -electrons are removed from the fuel - each electron travels with a proton- hydrogen atom | ||
| NAD+ >> NADH (represents stored energy that can be used to make ATP) | ||
| a byproduct of cellular respiration | ||
| 1. oxidative phosphorylation (90% of ATP produced) 2. Substrate-level phosphorylation (10% of ATP produced) | ||
| allosteric enzymes | ||
| - "Sugar Splitting" takes place in the cytosol - Glucose is split to form three-carbon sugars called pyruvate (pyruvic acid) -Energy investment phase -Energy Payoff phase (net energy payoff is 2 ATP, 2NADH) - No CO2 released - Takes place whether or not O2 is present! | ||
| - use 1 ATP, transfer one P and connect to glucose - Step 3 is the key regulatory step | ||
| - ATP is made - Pyruvate= final form payoff | ||
| - Occurs in the mitochondria of Eukaryotic cells/ cytosol of prokaryotic. - 8 enzymatic reactions for one turn of cycle.(x2) - 1 glucose>> 2 Acetyl CoA's ____________________________________ Outputs: (all x2 b.c. of second cycle) 1 NADH 3 NADH 1 ATP 1 FADH2 3 CO2 | ||
| -Molecules of NADH (and FADH2) account for most of the energy extracted from the glucose - This stage uses energy to power ATP synthesis ( inner membrane of mitochondria eukaryotic/ plasma membrane of prokaryotic) | ||
| - Sequence of Electron Carriers that pump protons into the intermembrane space. | ||
| -H+ gradient is established by the electron transport chain -H+ ions have a tendency to diffuse back across the membrane (down their gradient) - As H+ ions flow through ATP synthase, ATP is produced | ||
| -Glycolysis: +2 ATP -Citric Acid Cycle: +2 ATP -Oxidative Phosphorylation: +32-34 ATP | ||
| -Anaerobic Respiration - Fermentation (glycolysis, reactions that generate NAD+) ( Alcohol fermentation, lactic acid fermentation) |
